Windshield washer fluid for use in conjunction with windshield wipers has been available on vehicles at least since the mid-1930s. While available in a broad variety of formulations, most windshield washer fluid used today comprises about 40% methanol alcohol which is proven highly effective in eliminating insect remains from the vehicle windshield. (As an alternative to methanol alcohol some windshield washer fluid compositions use ethanol or ethylene glycol.) Additional ingredients include a blue dye from a powder and, in colder climates, methylated spirits to lower the freezing point of the washer fluid. Regardless of the formulation, most windshield washer fluids have an unpleasant odor.
In addition to improved methods for maintaining a clean windshield, other developments in vehicle passenger comfort have taken place concurrently, including ventilation systems. Today's modern heating, ventilation and air conditioning system (HVAC) system includes a variety of operator modes, including “fresh air” and “recirculation” modes. The fresh air mode is based on a system in which fresh air is brought from the outside into the vehicle. In most vehicles the fresh air intake is located between the trailing edge of the vehicle's engine hood and the leading edge of the vehicle's windshield.
Placement of the fresh air intake between the vehicle's engine hood and windshield has the advantage of orienting the intake proximate the vehicle's instrument panel and associated duct system. However, placement of the fresh air intake in this area also results in the fresh air intake being close to the windshield washer fluid spray nozzles. If the windshield washer fluid is used by the operator in conjunction with the windshield wipers while the HVAC is in the fresh air mode, very commonly the odor of the windshield washer fluid enters the vehicle cabin.
The situation described above may arguably be corrected if the vehicle operator is able to manually select the recirculation mode over the fresh air mode prior to engaging the windshield washer fluid, returning to the fresh air mode after the windshield has been cleaned. However, this approach is impractical and unlikely to be used often if at all.
As in so many areas of vehicle technology there is always room for improvement related to the use and operation of windshield washer fluid.